CVE-2026-66799

HIGHPre-NVD 7.87.8—
EchelonGraph scoreHIGH confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-08-11. the CNA's CVSS baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:microsoft, epss, ghsa
Trending — Patch released this week
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: None knownExposed: 0

A fix is available — apply it.

Heap-based buffer overflow in Windows Key Guard allows an authorized attacker to elevate privileges locally.

CVSS v3
7.8
EG Score
7.8(high)
EG Risk
35(Track)
EG Risk 35/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
19%
KEV
Not listed

Published

August 11, 2026

Last Modified

August 20, 2026

Advisory Details (1)

Auto-updated Aug 11, 2026
Patch available. Sources: microsoft.
microsoft Patch Available

Security Update Guide - Microsoft Security Response Center

Security Update Guide - Microsoft Security Response Center. Patch available via Microsoft Security Update

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66799

Vendor Advisories for CVE-2026-66799(3)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatrhacm2/cluster-backup-rhel9-operator:17869083092026-08-19redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 82× in last 7d / 131× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 131 total refreshes for this CVE.

  1. 2026-08-20 22:56 UTCEPSS rescore
  2. 2026-08-20 22:01 UTCVendor advisory
  3. 2026-08-20 22:01 UTCGHSA enrichment
  4. 2026-08-20 16:42 UTCVendor advisory
  5. 2026-08-20 16:42 UTCGHSA enrichment
  6. 2026-08-20 15:00 UTCVendor advisory
  7. 2026-08-20 15:00 UTCGHSA enrichment
  8. 2026-08-20 14:13 UTCVendor advisory
  9. 2026-08-20 14:13 UTCGHSA enrichment
  10. 2026-08-20 09:27 UTCVendor advisory
  11. 2026-08-20 09:27 UTCGHSA enrichment
  12. 2026-08-19 21:34 UTCVendor advisory
  13. 2026-08-19 21:34 UTCGHSA enrichment
  14. 2026-08-19 21:14 UTCVendor advisory
  15. 2026-08-19 21:14 UTCGHSA enrichment
  16. 2026-08-19 17:43 UTCEG score recompute
  17. 2026-08-19 17:43 UTCVendor advisory
  18. 2026-08-19 17:43 UTCGHSA enrichment
  19. 2026-08-19 17:04 UTCEPSS rescore
  20. 2026-08-19 16:50 UTCVendor advisory
  21. 2026-08-19 16:50 UTCGHSA enrichment
  22. 2026-08-19 15:13 UTCVendor advisory
  23. 2026-08-19 15:13 UTCGHSA enrichment
  24. 2026-08-19 14:30 UTCVendor advisory
  25. 2026-08-19 14:30 UTCGHSA enrichment
Show 75 more
  1. 2026-08-19 10:42 UTCVendor advisory
  2. 2026-08-19 10:42 UTCGHSA enrichment
  3. 2026-08-18 22:43 UTCGHSA enrichment
  4. 2026-08-18 22:12 UTCGHSA enrichment
  5. 2026-08-18 17:27 UTCEG score recompute
  6. 2026-08-18 17:27 UTCVendor advisory
  7. 2026-08-18 17:27 UTCGHSA enrichment
  8. 2026-08-18 13:48 UTCEPSS rescore
  9. 2026-08-18 13:44 UTCVendor advisory
  10. 2026-08-18 13:44 UTCGHSA enrichment
  11. 2026-08-18 06:08 UTCGHSA enrichment
  12. 2026-08-17 18:14 UTCVendor advisory
  13. 2026-08-17 18:13 UTCGHSA enrichment
  14. 2026-08-17 16:18 UTCEG score recompute
  15. 2026-08-17 16:18 UTCVendor advisory
  16. 2026-08-17 16:18 UTCGHSA enrichment
  17. 2026-08-17 13:47 UTCEPSS rescore
  18. 2026-08-17 07:15 UTCVendor advisory
  19. 2026-08-17 07:15 UTCGHSA enrichment
  20. 2026-08-16 19:22 UTCEG score recompute
  21. 2026-08-16 19:22 UTCVendor advisory
  22. 2026-08-16 19:22 UTCGHSA enrichment
  23. 2026-08-16 18:55 UTCVendor advisory
  24. 2026-08-16 18:55 UTCGHSA enrichment
  25. 2026-08-16 18:44 UTCVendor advisory
  26. 2026-08-16 18:44 UTCGHSA enrichment
  27. 2026-08-16 17:34 UTCVendor advisory
  28. 2026-08-16 17:34 UTCGHSA enrichment
  29. 2026-08-16 16:37 UTCEG score recompute
  30. 2026-08-16 16:37 UTCVendor advisory
  31. 2026-08-16 16:37 UTCGHSA enrichment
  32. 2026-08-16 14:56 UTCEPSS rescore
  33. 2026-08-16 09:42 UTCEG score recompute
  34. 2026-08-16 09:42 UTCVendor advisory
  35. 2026-08-16 09:42 UTCGHSA enrichment
  36. 2026-08-15 21:49 UTCVendor advisory
  37. 2026-08-15 21:49 UTCGHSA enrichment
  38. 2026-08-15 09:56 UTCEG score recompute
  39. 2026-08-15 09:56 UTCVendor advisory
  40. 2026-08-15 09:56 UTCGHSA enrichment
  41. 2026-08-15 01:30 UTCEPSS rescore
  42. 2026-08-14 22:02 UTCVendor advisory
  43. 2026-08-14 22:02 UTCGHSA enrichment
  44. 2026-08-14 21:17 UTCVendor advisory
  45. 2026-08-14 21:17 UTCGHSA enrichment
  46. 2026-08-14 20:26 UTCEG score recompute
  47. 2026-08-14 20:26 UTCVendor advisory
  48. 2026-08-14 20:26 UTCGHSA enrichment
  49. 2026-08-14 18:38 UTCEG score recompute
  50. 2026-08-14 18:38 UTCVendor advisory
  51. 2026-08-14 18:38 UTCGHSA enrichment
  52. 2026-08-14 17:34 UTCVendor advisory
  53. 2026-08-14 17:34 UTCGHSA enrichment
  54. 2026-08-14 16:47 UTCVendor advisory
  55. 2026-08-14 16:47 UTCGHSA enrichment
  56. 2026-08-14 16:28 UTCVendor advisory
  57. 2026-08-14 16:28 UTCGHSA enrichment
  58. 2026-08-14 05:44 UTCEG score recompute
  59. 2026-08-14 05:44 UTCVendor advisory
  60. 2026-08-14 05:44 UTCGHSA enrichment
  61. 2026-08-13 22:00 UTCEPSS rescore
  62. 2026-08-13 17:50 UTCVendor advisory
  63. 2026-08-13 17:50 UTCGHSA enrichment
  64. 2026-08-13 17:34 UTCVendor advisory
  65. 2026-08-13 17:34 UTCGHSA enrichment
  66. 2026-08-13 16:24 UTCVendor advisory
  67. 2026-08-13 16:24 UTCGHSA enrichment
  68. 2026-08-13 06:08 UTCVendor advisory
  69. 2026-08-13 06:08 UTCGHSA enrichment
  70. 2026-08-12 18:14 UTCVendor advisory
  71. 2026-08-12 18:14 UTCGHSA enrichment
  72. 2026-08-12 15:20 UTCEG score recompute
  73. 2026-08-12 15:20 UTCVendor advisory
  74. 2026-08-12 15:19 UTCGHSA enrichment
  75. 2026-08-12 13:51 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-66799?
CVE-2026-66799 is a high vulnerability published on August 11, 2026. Heap-based buffer overflow in Windows Key Guard allows an authorized attacker to elevate privileges locally.
When was CVE-2026-66799 disclosed?
CVE-2026-66799 was first published in the National Vulnerability Database on August 11, 2026, with the most recent update on August 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66799 actively exploited?
CVE-2026-66799 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 80.8% of all scored CVEs.
What is the CVSS score of CVE-2026-66799?
CVE-2026-66799 has a CVSS v4.0 base score of 7.8 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-66799?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66799, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-66799

Explore →

Is Your Infrastructure Affected by CVE-2026-66799?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs